About this replacement
Sharp SH001 / SH002 Series — 3.7V Li-ion Replacement Battery (SH001UAA)
This is a 3.7V, 750mAh Li-ion cell for the Sharp SH001, SH002, SH004, and SH005 smartphones. It replaces OEM part numbers SH001UAA and SH002UAA. Capacity figure is 2.78Wh as stated in the product specification.
- SH001–SH005 compatibility: These models share the same battery bay dimensions, connector pinout, and BMS handshake protocol. The cell form factor — 63.63 x 49.21 x 19.74mm — fits all four bays without modification. Voltage rail is identical across the series at 3.7V nominal.
- Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the SH001 platform. The BMS accepted the handshake on first connection, charge termination triggered correctly at full voltage, and the protection circuit tripped as expected under an over-discharge load test.
- Fuel gauge recalibration on first use: After installation, disable fast charging and run one full discharge-to-charge cycle at standard rate. The fuel gauge IC on this platform calibrates its coulomb counter against the new cell's discharge curve. Skip this step and the percentage readout will be off for weeks.
Why the SH001 reports wrong battery percentage after a cell swap
The Sharp SH001 uses a fuel gauge IC that stores a learned discharge curve from the previous cell. When a new cell goes in, the IC still references that old curve. The mismatch causes the OS to display percentage values that don't reflect actual charge state. Running one complete discharge cycle at standard current — without fast charging — forces the IC to rewrite its internal curve against the new cell. After that single cycle, percentage reporting stabilises.
Sudden shutdown at 20–30% on the replacement cell
This happens when the modem or display pulls a current spike that drops cell voltage below the BMS cutoff threshold — even though the reported percentage looks safe. A new cell at 750mAh has less voltage headroom under load than a higher-capacity cell would. If the phone shuts off abruptly in that 20–30% window, check that the BMS hasn't been tripped by a deep-discharge storage event. Charge the phone to 100% uninterrupted, then check that resting voltage reads at least 4.1V before powering on.